عنوان مقاله [English]
نویسنده [English]چکیده [English]
Precipitation is one of the most variable climatic elements that It Ìs changes Can have negative consequences on environmenta socialty, economics and even on The cultural societies. So, The purpose of this Project is identify The spatial and temporal characteristics of Rainy Days in a 20 year Period (1387-1367).
And circulation to environmental is used too.
For This purpose, 40 synoptic stations with the highest frequency recorded are used. In this study, the present climatic datas (ww) are set in eight Matrix to the nember of observation tims.
The Matrix Ìs columns represent the 40 stations and lines represent days of observation That is 7670 lines. Setting These datas in MATLAB soft ware and calculate the frequency of coding in done by using statistical methods.
The results of studies show that Plurial systems usually com from out of Iran That contain Siberian high- pressure , Sudan low pressure, dumb low pressure at ground level, Mediterranean and Red Sea and tropical high pressure in the middle levels of the atmosphere and the most important affective systems on the country Ìs precipitation and due to the long path, passed by these systems, in Iran the most of The precipitation are light .
Precipitation changes are affected by local factors including latitude and longitude, the heiht above sea level, farness and nearness to water sources. The direction of mountains,like Alborz and Zagros, wind ward and sunward ,Slopes, and external factors including : regional and Planetory systems of the general circulation of atmosphere ,Azor(March) and Esphand (February) have the hightes rate of monthly rainy days. And winter is the season of precipitation in counyry.